tracker-miner-fs: Improve efficiency of tracker:available updates
tracker-miner-fs: Improve efficiency of tracker:available updates

INSERT/DELETE {...} WHERE {...} with many solutions where no change is
necessary causes initialization to require more time and memory.

outofbits/tracker,hoheinzollern/tracker,outofbits/tracker,outofbits/tracker,hoheinzollern/tracker,outofbits/tracker,outofbits/tracker,outofbits/tracker,hoheinzollern/tracker,hoheinzollern/tracker,hoheinzollern/tracker,hoheinzollern/tracker,hoheinzollern/tracker,outofbits/tracker